X-ray diagnosis apparatuses, X-ray CT (computed tomography) systems, and mammography apparatuses are known as medical image diagnosis apparatuses for capturing an image of a subject.
For example, a mammography apparatus is used to acquire breast images of a subject. The breast images are interpreted and used to determine the presence of lesions such as breast cancer. In recent years, the rate of breast cancer has steadily been increasing, which has raised demand for early detection of lesions such as breast cancer.
The breast images include two-dimensional (2D) images (common mammography images) that contain layers of information in the thickness direction of the breast. Such 2D image is interpreted by a radiographic interpreter such as a radiologist. However, it is difficult to detect a lesion that overlaps with the mammary gland in the thickness direction of the breast.
Tomosynthesis is an imaging technique to produce three-dimensional (3D) image data including a plurality of tomographic images of the breast as a subject with a mammography apparatus.
In tomosynthesis imaging, X-rays of the subject are taken at different angles by using a mammography apparatus having a moving X-ray tube and an X-ray detector that are located facing each other with the subject between them. Projection data acquired by multiple times of radiography are reconstructed to generate 3D image data including a plurality of tomographic images.
A biopsy is sometimes performed to collect the tissue of a lesion detected by interpretation of radiographs with a puncture needle. In the biopsy, it is required to check the 3D position of the lesion. Therefore, an operator such as a doctor or the like searches for a tomographic image that demonstrates the lesion while switching display images from one tomographic image to another, and acquires the lesion in the tomographic image and its sectional position to check the 3D position of the lesion. This may force the operator to spend a long time switching display images to find out the lesion.
There is a method for checking the 3D position of the lesion. In this method, the lesion is specified in a common mammography image. Then, image analysis is performed on the mammography image and 3D image data to detect a position corresponding to the lesion from the 3D image data. The method requires two types of photography for capturing the common mammography image and the 3D image data, resulting in an increase in the radiation exposure of the subject. Besides, since the common mammography image and the 3D image data have different noise, the image analysis may have low accuracy. In this case, the position is detected from the 3D image data with low accuracy, and therefore it is difficult to check the 3D position of the lesion.